MARK Cavendish has claimed broken promises ahead of this year's Tour de France forced him to quit Team Sky.
The 27-year-old said he was left feeling like a "back-up rider" as Bradley Wiggins went on to claim a historic yellow-jersey success.
Cavendish, who moved to Omega Pharma-Quickstep last month, believes he could have also have captured the sprinters' green jersey and fulfil an ambition he thought Sky had held when he signed.
But the Manxman believes dreams of a Tour double were put on hold in the lead-up to the race as Sky instead focused on Wiggins.
"We didn't achieve what I thought we were setting out to achieve at the start of the season," he told The Daily Telegraph.
"Sky should have taken both jerseys. We could have done that without any risk or detriment to the yellow jersey. It's frustrating."
Cavendish, who won his only Tour green jersey last year, admitted Wiggins' success should always have been Sky's primary objective.
But while he was proud to be part of a famous summer for British cycling he suspected it would be his last with Sky after one of his support riders, Juan Antonio Flecha, was dropped from the Tour team.
"It was then, on the eve of the Tour, that I realised the promise I had signed to Sky on wasn't rally a promise," he said.
"I was a back-up rider. At the end of the day we weren't going for the two jerseys at all.
"It wasn't a failure, and I was very proud to be part of a British yellow-jersey winning team with Brad, but it wasn't the ultimate either."